CA1103274A

CA1103274A - PREPARATION OF N-(AMINOMETHYL)-.alpha.,.beta.-ETHYLENICALLY UNSATURATED CARBOXAMIDES AND THEIR POLYMERS

Info

Publication number: CA1103274A
Application number: CA316,485A
Authority: CA
Inventors: Charles J. Mcdonald
Original assignee: Dow Chemical Co
Current assignee: Dow Chemical Co
Priority date: 1977-12-02
Filing date: 1978-11-20
Publication date: 1981-06-16
Also published as: EP0002254B1; US4166828A; DE2861489D1; EP0002254A1; JPS5490113A

Abstract

ABSTRACT OF THE DISCLOSURE:
N-(aminomethyl)-.alpha.,.beta.-ethylenically unsaturated cationic carboxamides such as N-(dimethylaminomethyl)-acrylamide are readily prepared without coincident production of saturated impurities by reacting an .alpha.,.beta.--ethylenically unsaturated carboxamide such as acrylamide with a lower aldehyde such as formaldehyde and a secondary amine such as dimethylamine at a pH below 7. The resul-ting aminomethyl carboxamides are polymerized at a pH of 7 or less to form polymers containing essentially no gelled product.

Description

7~

PREPARATION OF N- (A~IIINO~ETHYL~ -ETTIYLENICALLY UNSATU~ATED
CARBOXAMI DE S AN D TTIE I R POLYME RS

This invention relates to a process for preparing cationic carboxamide monomers and their polymers.

Cationic polyacrylamides are known to be excel-lent flocculants for the treatment of sewage and aqueous suspensions of other organic and inorganic particulates.
Probably the best ~nown cationic polyacrylamides are those prepared by reacting polyacrylamide with formaldehyde in a dial~ylamine. See, for example, U.S. Patent Nos. 2,328,901;
3,539,535; and 3,979,348 as well as Suen and Schiller in Industrial Engineering Chemistry, Vol. 49, pages 21-32 (1956). Unfortunately, the cationic polyacrylamides pre-pared by these processes exhibit undesirable amine odors and are less stable than desired for many applications.

Attempts have been made to prepare su¢h cationic polyacrvlamides from corresponding cationic monbmers. See, for example, U.S. Patent Nos. 3,2S6,140. The results of such attempts have not been entirely satisfactory due to the s~stantial amount of saturated impurities resulting from the addition of the amine reactant across the ethy-lenic group of the acrylamide. Accordingly, as proposedin U.S. Patent l~os. 3,349,121 and 3,178,385, it has been 18,491-F

~ 32'7~

necessary to employ rather e.Yotic and expcnsive amines to minimize the formation of such saturated imyurities. Of-ten, -the polymers containing the residues of such exot;c amines clo not exh;bit the e.~ccellent flocculation characteristics of polymers prepared from the simpler dialkylamines. hloreover, it has often been observed that the cationic polyacrylamides prepared by polymerizing cationic acrylamides often contain substantial amounts of undesirable gelled or cross-lin~ed materials.
In view of the aforementioned deficiencies of the prior art methods, it ~ould be highly desirable to provide an economical process for preparing cationic carboxamides and polymers thereof which are odorless and essentially free of saturated impurities and gelled products except when cross-linking monomers are included and gel proclucts are expected.
The present invention relates to a process for the preparation of an ~-(aminomethyl)-~,~-ethylenically unsaturated cationic carboxamide by reacting an c~ ethylenically unsaturated carboxamide with an aldehyde having 1 to 3 carbons and a secondary amine, the carboxamide and the secondary amine being dispersible in the reaction medium characterized in that the p~l of the reaction mixture is less than 7 and that the mole % saturated impurity of the reaction product is not more than 10. The conditions of the reaction are sufficient to cause reaction of the carboxamide, aldehyde and amine to form at least 10 mole percent ~based on moles of carbocamide) of the desired N-(aminomethyl)-~,~-ethylenically unsaturated cationic carboxamide. Surprisingly, by conducting the reaction at a pH less than 7, the saturated impurity which would normally be expected to bè formed by the addition reaction of the amine to the ethylenic group of the carboxamide is minimized. The invention is also directed to a process for the preparation of a quaternized cationic carboxamide by reacting a cationic carboxamide with a quaternizing agent such as methyl chloride or dimethyl sulfate characterized in that the p}l of the reaction mixture is less D

3Z7~

tnan 7. ~y s~ sequel~tly polymerizing the quate~nized monomer, the problems normally experienced in carrylng out tile quaternization oE polymers of the ca-tionic car-boxamides, ~hich is a sensitive process, are averted.

The invention is further directed to a process for the preparation of a cationic carboxamide polymer characterized by subjecting the cationic carboxamide pre-pared by the process described above, to conditions of free radical initia-ted addition poly~eriza-tion at a pH
lQ less than 7. Surprisingly, by Garrying out the polymeri-zation of tile cationic carboxamide at a pH less than 7, a high molecular weight polymer which is essentially free of gelled or cross-linked polymer is obtained. Such high molecular weight polymers generally have weight average molecular weights (Mw) greater than 10,000, preferably greater than a million. These polymers have properties similar to those obtained under basic conditions, i.e., p~} greater than ~, and are essentially free of undesir-able amine odor.

2~ As would be expected, the cationic carboxamide polymers of the present invention are usefully employed in the flocculation of dispersed particulate solids from aqueous suspension, for example, sewage, effluents from paper manufacturing operations and industrial mining opera-~ions. l~oreover, these cationic polymers exhibit excellent activity as paper drainage and dry strength addi-tives.

Carboxamides suitably employed in the practice of this invention are those unsaturated compounds which contain one or more ~C=C~ (ethylenic ~roups) which are conjugated or isolated in relation to one or more carbox-Oamide (-C-NH-) radicals. Such carboxamides are advanta-~eously dispersible in the reaction medium under conditions 18,491-F

' . .. : ' I

~, . . .

_4_ ~ 2~

used in preoarin~; tiIe cationic carboY.amicIes. Preferably, the carboxamidcs are soluble in water under reaction con-ditions to be employed in preparin~ the cationic carbox-amide, i.e., they will Eorm at least a 5 weigIIt percent aqueous solution. Of particular interest in the present invention are the ~ r ~-ethylenically unsaturated aliphatic mollocal-boxamides r especially those represented by the structural formula:
,R10 CII2=C-CNH(R2) wherein Rl is hydrogen, alkyl or cycloalkyl and R2 is hydrogen, alkyl, hydroxyalkyl or similar substituent that is inert in the reaction to form the cationic carboxamide.
Preferably, Rl is hydrogen, methyl or ethyl and R2 is hydrogen, methyl, ethyl or hydroxyethyl, most preferably hydrogen. Exemplary preferred carboxamides include acryl-a~ide, methacrylamide, ethacrylamide, ~-methylmethacryl-amide, N-methylacrylamide, N-ethylacrylamide r and N-~ydroxy-- ethylacrylamider with acrylamide being most preferred.

2~ ~nines employed in the practice of -this invention are advantageously secondary amines which are dispersible in the reaction medium under conditions used to prepare the ca-tionic carboxamide. Preferably they are soluble in ~aterr i.e. r they will form at least a 5 weight percent aqueous solution. Of particular interest are secondary amines represented by the structural formula:

IIN(R3)2 II

wherein each R3 is individually hydrocarbyl such as alkylr c~rcloalkylr alkenylr aryl or arylalkyl or inertly substi-tuted hydrocarbyl such as hydroxyalkylr aminoalkylr sulfo-alkyl wherein sulfo is in acid or salt formr carboxyalkyl wherein carboxy is in acid or salt form or cyanoal}yl.
18,~91-F

''' ' ' ' ;274 --5~

Alternatively the R3 groups are collec-tively alkylene, al~enylene or other divalent hydrocarbon radical or iner-tly substi~uted cliradical which when ta~en with the amino nitro-gen forms a heterocyclic ring, preferably having 5 or 6 me~ers. The diradical, while predominantly hydrocarbon, may be al~ylaminoal~yl, alkoxyal]iyl, al]cylthioalkyl and the like. By `'inertly substituted`' is meant that the substituent is inert in the reaction forming the cationic carbo~amide. `'Hydrocarbyl" as used herein is a monovalent hydrocarbon radical. Prefer~bly, R3 is alkyl, especially lower alkyl having from 1 to 8 carbon atoms; hydroxy-alkyl, especially those having from 2 to 4 carbon atoms;
or alkenyl having from 3 to 8 carbon atoms. Exemplary amines include dimethylamine, methyle-thylamine, hydroxy-ethylmethylamine, dibutylamine, piperadine, morpholine,pyrrolidine, dietnanolamine, diallyl amine, N-methyl-aminoethane sulfonic acid, 2-aminopropionitrile and 2-[(~-methylamino)etllyl] pyridine. Of the foregoing amines, the dialkylamines such as diethylamine and dimethylamine are especially preferred.

For the purposes of this invention, it is under-stood that the term aldehyde includes those materials which will generate aldehydes having 1 to 3 carbons under the conditions of the process of this invention. Examples of aldehydes include formaldehyde, acetaldehyde and propion-aldenyde with formaldehyde being preferred. Examples of materials containing or having the capability of generating aldehydes include paraformaldehyde, formalin, and trioxy-methane.

The reaction of the unsaturated carboxamide with the amine and aldehyde is advantageously carried out in aqueous solution, preferably in a solution containing from 8 to 30 wei~ht percent of the unsaturated carboxamide, from 4 to 14 weight percent of aldehyde and from 5 to 20 18,491-F

~ j ..

' . ~
,' -27~

wei~ht percent OL -the suitable amine. The recited concen-tration ran~e of amine is given as weight percent of free amine, even thou~h ~he amine is generally in salt ~orm under reaction conditions.

Althou~h not critical, it is often desirable to pre-react the secondary amine with aldehyde to form an adduct which is subse~uently reacted with the unsaturated carboxamide in an aqueous medi~n. In such instances, the adduct is normally pr~Qpared by reacting an aqueous solution of aldehyde with the suitable amine. While the,reaction may take place at ambient or elevated temperatures, the reaction proceeds at a sufficiently rapid rate in most instances at ambient temperature. The molar ratio of the aldehyde to the amine may vary over a wide range but the preferred ratio is usually within the range from 10 to 1 to 1 to 10, most preferably, a ratio of aldehyde to amine from 2 to 1 to 1 to 2. While it is generally desirable to prepare tnis adduct in as concentrated a form as possi-ble in order to minimize dilution effects, the concentration 20 of the adduct in the aqueous medium should he from 30 to 60 ~eight percent, most preferably from 38 to 53 wei~ht percent. The amine contribution is calculated as if it were ree amine even thou~h it may be in salt form.

In reactin~ the aldehyde and amine separately or as the adduct with the unsaturated carboxamide, the aqueous reaction mixture is maintained at a pH less than 7, pre-~erably from 0.02 to 4 and most preferably from~ll to 2.5.
The temperature of the reaction is not particularly criti-cal and is suitably any temperature which provides the desired reaction. Generally, however, the reaction tem-perature ran~es from 20 to 90C, preferably from 30 to 60~C. While the reaction time required to achieve the desired conversion to cationic carboxamide will decrease as temperature increases, effective reaction normally occurs withill 60 to 2~0 minutes at intermediate reaction 18,491-F

, ' . ~` ' ':
,.
.. ' :
- ' , ' ' ` ~

~S3~

temperatures rrom 40 to 65~C. In any event, the reac-tion is continued for a period of time sufEicient to convert the carboxainide moiety to the desired cationic Eorm.

As mentioned hereil~before, -the pEI of the reaction mixture is critical. Therefore, it is desirable that the reactants as they are supplied to the reaction mixture be maintained at pH's below the aforementioned critical limit.
Accordingly, one approach is to acidify the reaction mix-ture and/or reactants being supplied to the reaction mixture witla hydrogen chloride or some other strong acid.
Following formation of the desired cationic carboxamide, the product of the reaction may be isolated if desired or used in its crude form. In either case, it is advantageous to maintain the reaction product at pH of less than 7, preferably less than 5, at least until all of unreacted amine has been removed from the reaction product. In the case when dimethylamine or other dial]~yl amine, formalde-hyde and acrylamide are -the reactants, it is desirable to maintain the reaction mixture at a pH below 5, preferably at 3 or less, most preferably from 1 to 2.5. Moreover, it is generally found that the cationic carboxamide is more stable at such lower pH's, even when no unreacted amine is present.

While the reaction is suitably carried out in a reaction medium that is essentially aqueous, the reac-2~ tion is also usefully practiced in a medium that isessentially a water-in-oil emulsion. In such plractice, aqueous solutions of one or more of the reactants are dis-persed in an oil phase usually with the aid of a water-in--oil emulsifier. The proportions of ingredients (i.e., oil phase, aqueous phase, emulsifier, etc.) in such prac-tices are similar to those conventionally employed in ~ater-in-oil polymerization of water-soluble monomers, e.g., as in U.S. Patent 3,284,393 and water-in-oil Mannich reac-tions, e.g., U.S. ~atent 3,979,349.
18,491-F
.

~ r~
--S

Ill carîying out the reaction to form -the cationic carboxamide, it is oEten clesirable to include a small amoullt of a polymerization inhihi-tor, such as hydroquinone, t-but~lpyrocatechol, phellolthiazane, ancl coppcr sulfate, in conventional clucultities from 0.0~ to 0.1 wcicJht percent based on t~e carboxamide reac-tant.

The cationic carboxamide reaction product obtained in the practice oE this invention has the general appear-ance of an oil which is soluble in water to a certain o degree. The resulting preferred cationic carboxamides are represented by the forrnula:
,1,, CH2=C-CN-CH-N(R3)2 wherein Rl, R2 and R3 are as defined hereinbefore and R4 is hydrogen or al~yl having 1 or 2 carbons. Especially prefeLred ca-tionic carboxarnides are ~-(dimethylamino-methyl)acrylamide, N-(diethylaminomethyl)acrylamide and N-(diallylaminomethyl)acrylamide. These cationic carbox-2~ amides polymerize readily under condi-tions of addition polymerization normally employed in polymerizing water soluble monomers.

In the polymerization of the resulting cationic carboxamide, the cationic carboxamide is subjected to poly~
merization conditions which are generally conventional for the free radical initiated addition polymerization of carboxamide and N-substituted carboxaïnide monomers except that the polymerization is carried out at a pI~ below 7, preferably from 2 to 4. For example, the cationic carbox-amide, advantageously dissolved or dispersed in an aqueousmedium containing a free radical generating initiator such as a peroxide or an azo-type initiator, is subjected to pGlymerization conditions such as ~eïnperatures from 20 to 18,491-F

_9~

60C, preEerably ~rolll 25 to ~0C. Th:is polymerization is advanta~eously carried out at approximately atmospheric pressure ~Jherein the gas over the reaction mi~ture is essentially free of oxygell and is pre~erably a gas iner-t to the polymerizatior. such as ni-trogen. The molecular wei~ht of the polymer may be regulated by conventional chain transfer agents. As wit:h the reaction to form the cationic car~oxamide, the polymeriza-tion o~ the cationic carboxamide may also be carried out in a water-in-oil emulsion, e.g., by the process described in U.S. Patent

3,284,393.

The resulting polymer is then recovered by conventional procedures and may be em-ployed itself as a flocculating agent or may be qua'ernized to form a polymer havin~ further enhanced flocculating characteristics. Such quaternization reactions are ~Yell known and may be con-ducted by contacting the resulting polymer with a qua-ternizing agent such as an alkyl halide, or a dialkyl sulfate such as dimethyl sulfate. Preferably in such ~o quaternizing agents, alkyl has one or two carbons.
Examples of preferred quaternizing agents include methyl chloride, dimethyl sul~ate, and methyl bromide. Suitable conditions for quaternization of the polymer are described in British Patent 887,900.

In some instances, it may be desirable to qua-ternize the unsaturated cationic carboxamide prior to polymerization. In such instances, the quaterni;zation reaction is carried out under conventional conditions men-tioned abo~e except that the pH of the reaction mixture during quaternization is carefully maintained below a pH
of 7, preferably a pH from 3 to 5. Following quaterniza-tion of the monomer, it may be recovered in e~ssentially pure form prior to polymerization or the resulting quaternization 18,491-F

-10- ~ 14 mixture may be subject -to polymerization conditions similar to those employ~d in polymerizing the cationic carboxamide.

The followiny examples are given to illustrate the invention but should not be construed as limiting the scope thereof. Unless otherwise in~icated, all parts and percentages of these examples are by weight. The resulting compositions are analyzed by employing carbon magnetic resonance spectroscopy.

Example 1 To a 3-nec]ced, round-bottom flask equipped with a thermometer, magnetic stirrer and a pH electrode are added 1 par-t of paraformaldehyde containing 96 percent of formaldehyde and 3.71 parts of a 40 percent aqueous solu-tion of dimethylamine. The paraformaldehyde is added slowly to control the reaction temperature below 45C.
fter a reaction time of 2 hours, the resulting formaldehyde amine adduc-t is then acidified to a pH of 2 by slowl~ adding 3.7 parts of a 38 percent aqueous solution of hydrochloric acid. During the addition of the hydrochloric acid, the reaction mixture is cooled with an ice bath to maintain the reaction mixture at a temperature below 20C.

The resulting acidified product is then added to 4.72 parts of a 48 percent aqueous solution of acryl-amide which has previously been acidified with hydrochloric acid to a pH of 2. The resulting mixture is heated to 65C
and maintained there with stirring for a period~of 2 hours.
The resulting composition is analyzed and found to contain 85 mole percent of N-(dimethylaminomethyl)acrylamide and less than 5 mole percent of saturated impurity.

Examples 2 and 3 and Comparative Runs A and B
For purposes of showing the preference for carrying out the process of this invention at pH of 3 or 18,~l91-F

less when using rea~ents of Exc~lple 1. Examples 2 and 3 are made accordin~ to the following procedure.

To the apparatus used in Example 1 are added 7~.2 parts of a 40 percent solution oE dirnethylamine and then slowly 57.1 parts of 37 percent of formaldehyde in aqueous solution. The resul-tin~ reaction gives an exotherm at 25C within 4 minutes of the addition oE the formalde-hyde. The resultin~ reaction mixture contains 39 percent solids of primarily dimethylaminomethanol. This clear product is cooled to 10C and acidified with hydrochloric acid to pl~ 2.0 for Example 2 and to pll 3.0 for Example 3 as listed in Table I.

The acidified dimethylæminome-thanol is then added to a 50 percent aqueous solution of acrylamide also acidified with hydrochloric acid to the p~ listed in Table I. The resulting reaction mixture is subjected to a hea-t histo~y sufficient to ensure maximum conversion to the desired N-~dimethylaminomethyl)acrylamide. This heat history varies from 3 to 6 hours at 40~C. The resul-ting product is analyzed and found to contain the pro-portions of N-substituted acrylamide, acrylamide, and saturated impurity as indicated in Table I.

For purposes of comparison, Comparative Runs A and B are carried out following the general procedure described hereinbefore except that the pH of the reaction mixture is 7.0 and 5.0, respectively. The results of these runs are also reported in Table I.

1~,491-F

Q~
~`P
h ~ c~
~' o~
0~ ~,.
U~ ~

C~o~
O ~ I` ~ t~
~1 ~ ~`1 (`1 V ~1 H ~_ d C U ~ C~
a) ~ ~ ~D V
O ~

a~
.~ :
C O O O O

.C ~.

CO
~: m ~ ~; C

X o o 18, 491-F

3Z7~

As evidencecl by the data oE Table I, it is critical to prac-tice the me-thod Gf this invention at pI~'s below 7 in order to obtain any yield of the desired N-s~stituted acrylamide. In order to obtain suitable yields of tlle ca-tionic acrylamicle, it is desirable to employ a p~l of less than 5, preferc~ly 3 or less. In this regard, i-t should be no-ted that of all carboxamides, acryl-amide e,Yhibits the greatest tendency to form saturated impurity at p~l in the range of 5 to 7. Accordingly, the reaction mixture pH of 5 to 7 is suitable i~ other carbox-amides, such as methacrylamide, are employed.

Examples 4 and 5 Following the procedure of Example 2, Examples

4 and 5 are carried out to show the effect of heat history on the N-substituted acrylamide. In Example 4, the reac-tion is carried out at 40C for 11 hours and the resulting product is analyzed for N-substituted acrylamide, acrylamide and saturated impurity. In Example 5, the reaction is also carried out at 40C and the reaction product is maintained at that temperature for a period of 26 hours. The product of this reactioll is similarly analyzed. The results of analysis for both runs are reported in Table II.
. .
TABLE II

Reaction Mole %
Time, Mole % Mole % Saturated hours D~M~AM (1) AAM (2) Impurity :
Example 4 11 75 22 ' 3 Example 5 26 79 11 10 (1) N-(dimethylaminomethyl)acrylamide (2) Acrylamide 18,491-F

3;~7~

~s e~idenc~d by the data shown in Tab]e II, great~r c~mcul~ts oE the saturatecl impurity are yenerally formed wnell loncJer reaction times are employed.

Example 6 Follo-~ing the proced~lre of Example 1, a dimethyl-aminomethanol adduct is prepared, acidi~ied and cooled.
This adduct is added to 18.2 parts of a 15 percent aqueous solution o~ methacrylamide which has ~een previously acidi-fied to a p~l of 2. The resultillg mixture is heated for 2 hours at 65~C. Results of the analysis indicate that the final reaction product contains 75 mole percent of N-(dimetllylaminomethyl)methacrylamide~

Example 7 To the apparatus employed in Example 1, is added 81.1 parts of a formalin solution containing 37 percent of formaldehyde and 147.0 parts of a 48.2 percent aqueous soluLion of acryiamide, both o~ which have been acidified with hydrochloric acid to a pH of 2. To this homogeneous solution are added lQ0 parts of an aqueous amine reayent containiny 97 percent of diallylamine in a remaining amount of 38 percent hydrochloric acid. This reagent also has a pH of 2. The resulting reaction mixture is heated at 65C
for 2 hours. Analysis of the resulting reaction product indicates conversion to 80 mole percent of N-(diallylamino-methyl)acrylamide.

Example B
To the apparatus of Example 1 are added equalmolar amounts of formalin containiny 37 percent formaldehyde, 22.2 percent aqueous solution of diethylamine and 47,6 percent aqueous solution of acrylamide, all acidified to a pH of 2. The resulting mixture is heated with stirring at 60C for 3 hours. Analysis of the resulting product 18,491-F

.

, ~U3~

indicates a product containing greater than 75 mole per-cent of ~-(diethylaminom~thyl)acrylan~ide.
.

Example 9 In a reaction vessel equipped with thermometer and pH electrode are added 5 parts o a 38 percent aqueous solution (p~l of 2) of the cationic acrylamide monomer of Example 1 and 2 parts of a greater than 99 percent pure dimethylsulfate reagent~ An aqueous solution of 50 percent sodium hydroxide is then addecl portionwise to the hetero-geneous mixture to maintain the pH around 3. As thequaternization reaction proceeds, the temperature is main-tained between 30 to 35C. The clear product comprises greater than 30 mole percent of N-(trimethylammoniummethyl)-acrylamide salt and less than 5 mole percent saturated by-product.

~xample 10 Into a 500 ml resin pot equipped Wi~l a stirrer, thermometer, and nitrogen purge tube are added 75 parts of a 30 percent aqueous solution (pH of 1) of the cationic acrylamide of Example 1 and 375 parts of deionized water.
The mixture is adjusted to a pH of 3 with a 50 percent aqueous solution of sodium nydroxide and purged for one hour with nitrogan. As initia-tor, an aqueous solution of a conventional redox catalyst consisting of sodium persul-fate-sodium metabisulfate is injected simultaneously tnrough a port into the vessel. The reaction is allowed to proceed over a 2-hour period at 3aoc. The resulting viscous polymer solution is then heated to 50~C and a second shot of the aforementioned initiator is introduced.
After the polymerization recipe is heated for 2 hours at 65C, the polymerization is terminated and the resulting polymer of the cationic acrylamide is recovered.

18,491-F

' : ', : . ' -16- ~ ~ 3~t7~

Example 11 To the resin pot similar to the one used in Example 10 is added a water-in-oil emulsion containing the following ingredients:

298 parts of a 36 percent aqueous solution (pH of 3) of the cationic acrylamide of Example 1, 56 par-ts of deionizeld ~7ater, 140 pa.rts of Isopar~ ~1 (a mixture of isoparaffinic hydrocarbons having a flash point of 77C) and .
11 parts of isopropanolamide of oleic acid.

The resin pot containing tne foregoing emulsion is heated to 30C and purged ~7ith nitroyen for one hour. Polymeri-zation of the recipe at pH of 3 is effected by adding the conventional redox catalyst of Example 10 to the recipe and maintaining the recipe at 30C for 3 hours. The recipe is then heated at 50C for one hour to yield a water-in--oil emulsion of poly[N-(dimethylaminomethyl)acrylamide].

18,491-F

.

.

Claims

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. A process for the preparation of an N-(aminomethyl)-.alpha.,.beta.-ethylenically unsaturated cationic carboxamide by reacting an .alpha.,.beta.-ethylenically unsaturated carboxamide with an aldehyde having 1 to 3 carbons and a secondary amine, the carboxamide and the secondary amine being dispersible in the reaction medium characterized in that the pH of the reaction mixture is less than 7 and that the mole % saturated impurity of the reaction product is not more than 10.

2. The process of claim 1 characterized in that the pH of the reaction mixture is less than 5.

3. The process of claim 1 characterized in that the pH of the reaction mixture is 3 or less.

4. The process of claim 1 characterized in that the reaction mixture is dissolved in an aqueous medium and dispersed in an oil phase to form a water-in-oil emulsion prior to the reaction to form the cationic carboxamide.

5. The process of claim 1 which comprises the further step of subjecting the cationic carboxamide prepared by the process of claim 1 to conditions of free radical initiated addition polymerization at a pH of less than 7.

6. The process of claim 5 characterized in that the cationic carboxamide is dissolved in the aqueous phase of a water-in-oil emulsion and is subjected to polymerization conditions which results in the aqueous phase containing the polymer.